Radio frequency devices can store credential information that can be used later for authentication of the user. This authentication can be accomplished using various protocols, including Wi-Fi, Bluetooth, or protocols more typically used by contactless smartcards. When presented to a reader/interrogator a contactless smartcard transmits the stored credential information for verification by the reader/interrogator. The reader/interrogator processes or can access the credential information and can determine if the device being presented is valid. If the reader/interrogator determines that the credential information from the device is valid then the reader/interrogator can initiate any number of actions allowing the holder of the device access an asset or complete a transaction. Radio frequency devices that are used for authentication in this way typically make use of short-range wireless communication for this purpose, notwithstanding the fact that the device may also be capable of longer-range, higher-power voice or data communication. However, any type of wireless communication standard can be used for authentication as described.
NFC (“near field communication”) is a communication method that is showing great promise for communication between devices at short range. NFC is the protocol that is used by contactless smartcards working at 13.56 MHz. The communication protocol of a typical NFC chip can be seen for instance in Short Form Specification of the PN511-Transmission module, February 2004, from Philips Semiconductors, which is herein incorporated by reference in its entirety. The protocol used in NFC can vary depending on the mode of operation of the chip and reader/interrogator. For example, if an active NFC mode is used, a reader/interrogator is powered to generate an RF field. The target device has its own power supply for digital processing and communications. When the target device receives a communication from a reader/interrogator, the target device can use its own power supply to generate another RF field to answer the reader/interrogator. Alternatively, if a passive NFC mode is implemented, the target device answers a reader/interrogator command using a load modulation scheme. The target device is not powered; rather, the target device uses energy from the RF field created by the reader/interrogator.
NFC capabilities can be included in a smartphone so that the smartphone becomes a target device and can be used for authentication as described above. Many modern smartphones are also equipped with touch screens to handle user I/O. Such a device can interpret gestures that correspond to or take place in pre-defined areas of the screen as if the user is manipulating objects or icons that are pictured on the screen. Tablet computers and even some notebook computers can provide similar I/O capabilities.